There is a supplement for dogs that has Cumin and Turmeric, it also has antiinflammatory properties as well as use for cancer. It is called Curcuvet, it's also really inexpensive. FYI it may result with your dog producing odiferous gas until he's used to it. It was recommended by my dogs accupuncturist.
I have not used rimadyl for cancer but did have a patient with a uncommon cancer on his nose that I used the piroxicam per Auburn's oncology folks. It is more expensive but I was amazed at how well he did and how long it was before he needed to be euthanized. He did happen to be a lab. Debbie Darche, DVM